Re: History for query replace pairs

[Juri Linkov <juri@jurta.org>]

> I briefly tried it (will do more testing once NEWS or the manual

It's too early to describe it in the manual because it might require
more changes after testing.  And to announce it in NEWS we need
something more substantial such as to add an option to enable/disable
this feature.

> describes the feature in detail), and saw one problem: the Unicode
> character → (u+2192) is a problem on TTYs that can't encode it or on
> GUI frames that use font without a glyph for it.  So I think we need a
> fallback for those cases (e.g., using char-displayable-p to detect them).

When I tried to use char-displayable-p in defcustom, then
bootstraping failed with the error

  Attempt to autoload char-displayable-p while preparing to dump

because replace.el is preloaded, and we don't know whether the character
will be displayable on the current display.

I wonder is it possible to detect undisplayable characters in the
display engine and perform the normalization using the rules
for confusable characters?

In lisp/international/latin1-disp.el in latin1-display-ucs-per-lynx I see
the mapping (?\→ "->").  Could it be used for an automatic fallback?